RE: Sailplane Wing Design Round II
If you wrap the spar with bias light glass, rather than the kevlar wrap, you don't need to use vertical grain balsa. You can just use horizontal grain. This will save you some time and weight and make the dimensions of the final spar more predictable. You can mist the spar with Super 77, lay it on some smoothed out 2 ounce fiberglass and roll the spar so no wrinkles are present. Then brush on the laminating resin. It's important that the fiber oreintation of the glass be at 45* to the length of the spar. Another option is to find some light braided fiberglass sock/tubing. You can slide it over the spar, stretch it tight, and then saturate.